Minimally-invasive surgical procedures frequently involve insertion of instruments into a body cavity through a tissue puncture site. Examples of such procedures include insertion of vascular catheters through a puncture site in a blood vessel and insertion of laparoscopic instruments through a puncture site in the abdominal wall. (In the context of the present patent application and in the claims, the term “cavity” is used broadly to refer to any and all sorts of volumes inside the body, including lumens, such as blood vessels.) It is desirable, in order to facilitate healing and reduce complications, to suture the puncture site shut at the end of the procedure. Although the skin at the outer end of the puncture can easily be sutured, it is difficult to access and suture the internal tissues (such as the intima of the blood vessel or the abdominal fascia) through the puncture. Therefore, at the end of a vascular catheterization procedure, for example, many cardiologists and invasive radiologists simply press on the puncture site mechanically to achieve homeostasis. This mechanical technique requires the patient to remain immobilized for a long time (typically 2-8 hours), and increases the risk of subsequent bleeding.
A number of specialized instruments have been developed for percutaneous suturing of vascular puncture sites. For example, U.S. Pat. No. 5,417,600, whose disclosure is incorporated herein by reference, describes a suture applying device that comprises a shaft with a pair of needles near its distal end. The needles are joined by a length of suture. The shaft is used to introduce the needles into a lumen of a body structure and then to push the needles back through tissue on either side of the puncture site. After the needles have passed through the tissue, they are drawn outward, leaving a loop of suture behind to close the puncture site.
As another example, U.S. Pat. No. 5,868,762, whose disclosure is incorporated herein by reference, describes a device for suturing a vascular puncture site. The device includes a shaft having a distal end terminating in a pair of resilient prongs. Each of the prongs carries a suture anchor, attached to one end of a suture. The shaft is introduced into the puncture site, whereupon the prongs expand to an open position, thus positioning the suture anchors for penetration of the vascular wall by manipulation of the shaft. The prongs are then retracted, leaving the suture anchors to secure the sutures to the vascular wall tissue.
U.S. Pat. No. 6,245,079, whose disclosure is incorporated herein by reference, describes a suturing device having a distal portion that is inserted percutaneously through an incision into a blood vessel. The distal portion has two retractable arms, which extend and hold a suture within the blood vessel. Retractable needles are deployed from the device to pierce the vessel wall, release the suture ends from the retractable arms, and then pull the suture through the vessel wall.
Other exemplary devices and methods for suturing internal puncture sites are described in U.S. Pat. Nos. 6,517,553, 6,451,031 and 5,411,481, whose disclosures are incorporated herein by reference.